I just experienced this Upgrade: Denied problem for the first time.

I had a segment waitlisted with an SWU that is part of an international ticket. IAD-SEA showed as Upgrade: Waitlisted via the SWU. As soon as the UDU window hit and no NF seats were open it went to Upgrade: Denied. I called UA to confirm all was OK and the agent was confused why I would be seeing Upgrade: Denied. She assured me that I was on a "priority waitlist".

Today the upgrade cleared. The reservation now only has one entry for IAD-SEA but it still says Upgrade: Denied. I'm able to pick a seat in F with no problem and it sticks so I doubt I'll have any issues at the airport when I check-in.

This is one situation where I don't want to bring a printout of the reservation with me because they can point to the Upgrade: Denied wording and actually deny my upgrade Seems like per the other posts in this thread that I shouldn't expect any problems anyway.

-RM